Wafer-level manufacture of camera modules manufactured with complementary metal-oxide semiconductor (CMOS) technologies has contributed to the incorporation of camera modules in high-volume consumer products such as mobile devices and motor vehicles.
FIG. 1 shows a wafer-level lens 100 incorporated into a camera module 192 of a mobile device 190. FIG. 2 is a cross-sectional view of a prior-art lens 200 that is an example of wafer-level lens 100. Prior art lens includes two planar substrates 211, 212, and resin lenses 221-224. A spacer 231 separates planar substrates 211 and 212. Lens 200 has a height 202. Planar substrate 212 is on a spacer 232 such that lens 200 may be positioned above an image sensor, not shown, of camera module 192.
Lens 200 has several disadvantages. Shapes of resin lenses 221-224 have limited accessible thicknesses and curvatures because larger thicknesses and curvatures contribute to lower replication yields. Planar substrates 211 and 212 have respective thicknesses 241 and 242. Resin lenses 221-224 have respective maximum thicknesses 243-246. Thicknesses 243-246 place a lower limit on height 202. For example, thicknesses 244 and 245 place a lower limit on a distance 204 between planar substrates 211 and 212. If lens 200 is used in mobile device 190, thicknesses 243-246 place a lower limit on the thickness of camera module 192, and hence constrains how thin mobile device 190 can be.